This may be the first free service I ever actually donated money to- and the first to which I donated Euros, no less.

LJBook can make a PDF document out of as much or as little of your journal or community's archives as you like. Entries as well as comments. It's a (FREE) web service, so you don't have to download/fight with any client software. I just used it to back up three years worth of Star Trek role-playing (over two thousand pages, woo!). My only complaint is that all the break-lines get taken out of comments, so the comments look like this:

"Hi, here's what one character says!" "Here's what another character says." "Oops, back to the first character again." "May I have a turn?" asks another. Here's where a new paragraph should start. Damn, this is confusing. "Oh no, someone's talking again..."

But that's not as important to me as having a backup of the text, just in case SixApart's servers ever catastrophically die or something. I dunno, maybe I'm the only weirdo who really enjoys rereading old journal/RPG posts, but perhaps others here will find this useful...?